Question

An 18-year-old G1P0 parturient with a history of systemic lupus was diagnosed with mild preeclampsia at 27 weeks gestation. She remained stable on weekly evaluations. Now, at 32 weeks gestation, she experienced the start of contractions in the middle of the night. Aft er evaluation, the obstetrician decides to initiate tocolysis with a 4-g bolus of magnesium sulfate, followed by an infusion of 2 g/hr. The following morning the patient is lethargic and has an oxygen saturation of 85%. In addition to oxygen by facemask and discontinuing the magnesium infusion, appropriate initial therapy would include

A. Ordering an echocardiogram to rule out peripartum cardiomyopathy
B. Furosemide, 40 mg IV
C. Evaluation for evidence of myocardial ischemia, including EKG and serum troponin levels
D. Sublingual nitroglycerin tablets, until an infusion of nitroglycerin can be initiated
E. Calcium gluconate, 500 mg IV

Answer 1

In the case of suspected magnesium sulfate toxicity in a pregnant patient with preeclampsia, the recommended initial treatment includes administering calcium gluconate as an antidote along with discontinuing the magnesium infusion and supplying supplemental oxygen.

Step-by-step explanation:

An 18-year-old G1P0 parturient with a history of systemic lupus and diagnosed with mild preeclampsia is now presenting with lethargy and decreased oxygen saturation after receiving a bolus and infusion of magnesium sulfate for tocolysis. Considering the signs of potential magnesium sulfate toxicity, the appropriate initial therapy would include administering calcium gluconate, which acts as an antidote by antagonizing the effects of magnesium on neuromuscular junctions. Immediate intervention also includes discontinuing the magnesium infusion and providing oxygen by facemask.